Charge Asymmetries in the Angular Distribution ofπandKMesons from Antiproton Annihilations in Flight

Abstract

A difference in the angular distributions of positive and negative pi and K mesons produced in p-barp annihilations was sought for the center of mass momentum 657 plus or minus 16 Mev/c (1.6 Bev/c in the lab). The analysis was done on two samples of events: 1620 events of the type p-bar + p yields n pi with n =4to 8 and 287 events of the type p-bar+ p yields K-bar + K + n pi , n = 1 to 4 and at least one of the K mesons was observed to decay in the chamber. These events were observed inside a central volume of a 72-inch bubble chamber. The average antiproton momentum at the point of interaction was 1.61 approximately 0.04 Bev/c (925 Mev kinetic energy) for the first sample mentioned and for 86% of the second. The remainder of the second sample was at 1.99 plus or minus 0.05 Bev/c. The angular distribution obtained indicates a possibility that two different amihilation mechanisms are operative: the statistical one, which is dominant and produces an isotropic angular distribution; and a dynamical mechanism. (L.N.N.)